【代码笔记】Web-JavaScript-JavaScript 变量

一，效果图。

二，代码。

<!DOCTYPE html>

<html>

<head>

    <meta charset="utf-8">

    <title>javascript 变量</title>

</head>

<body>

    <script>

    var x = 5;

    var y = 6;

    var z = x + y;

    document.write(x + "<br>");

    document.write(y + "<br");

    document.write(z = "<br>");

    </script>

    <script>

    var pi = 3.14;

    var name = "bill gate";

    var answer = "yes i am ";

    document.write(pi + "<br>");

    document.write(name + "<br>");

    document.write(answer + "<br>");

    </script>

    <p>点这里来创建变量，并显示结果</p>

    <button onclick="myFunction()">点击这里</button>

    <p id="demo"></p>

    <script>

    function myFunction() {

        var carname = "volvo";

        document.getElementById("demo").innerHTML = carname;

    }

    </script>

    <p>假设 y=5，计算 x=y+2，并显示结果</p>

    <button onclick="myFunction()">点击这里</button>

    <p id="demo"></p>

    <script>

    function myFunction() {

        var y = 5;

        var x = y + 2;

        var demoP = document.getElementById("demo");

        demoP.innerHTML = "x=" + x;

    }

    </script>

</body>

</html>

参考资料：《菜鸟教程》

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【代码笔记】Web-JavaScript-JavaScript 变量

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